The present invention relates to a device for the electrically conductive connecting of a liquid-crystal cell to a printed circuit board.
Various devices are already known for connecting a liquid-crystal cell to a printed circuit board which bears, in particular, a control circuit. One such device which is frequently used contains a conductive gum -- also known as zebra stripes. This conductive gum is in the shape of a bar of rectangular cross section and consists of a plurality of disks which fill up its cross section, an insulating disk and a conductive disk alternating with each other. A continuous insulating layer can then be applied on two opposite sides.
These conductive gums have in fact found wide use. However, the reliability and permanence of such contacts still needs improvement. Furthermore, conductive gums have been known solely for connecting conductive paths which are arranged on parallel boards arranged facing each other.
For reasons of construction it may, however, be advantageous to arrange the circuit board at right angles to the liquid-crystal cell. Particularly in the case of liquid-crystal cells with negative display of the characters and symbols, illumination from the rear is advantageous and, for this purpose, a structural shape with circuit board and liquid-crystal cell at right angles to each other is desirable.
For the connecting of circuit boards which are at right angles to each other, various multiple-plug devices have, it is true, become known but they are more subject to corrosion than contacting by means of conductive gum because of the lack of protection of the contacts. Furthermore, such multiple-plug connections are relatively expensive and are not available for such a small spacing between contacts as is required for connecting liquid-crystal cells, particularly dot matrix displays, to the control electronics.